Watch your boost on both pulleys. If the belt is slipping any, you'll be able to see the boost come on/off/on/off unless it's slipping really badly, in which case you should have telltale rubber on the underside of the hood.
Anything that increases out flow drops boost. The most I ever saw on a 3.4 setup with a HAI and headers was 8 psi with a ported Gen 3.
I'm now at 16psi on a 3.0/IC/Cammed/ all that good stuff.
The PLOG and DP help quite a bit, and without having any knock, that's a good thing. Headers would net you more flow and more room to pulley down or pull more timing.
